Manufacture of thread or the like



Feb. 5, 194.6. H. B. KLINE ETAL 2,394,519

MANUFAGTURE oF THREAD OREHE LIKE Filed July 29, 1940 3 Sheets-Sheet 1 2s z5 Y as O as Z4 22 v a 24- 4 l n n FI [il 1 n n I- l IZ o la l2.

I3 I 'o IZ, I6 I2.

l5 5 Q I4 I6 :Inventur:

HAYDEN E KLlNl-z 9 Lows SFRYER OBERTDMACLAURIN ttamgg H. B.KL|NE ET AL NANUFAGTURE 0F THREAD 0R THE LIKE Feb. 5, 1946. -v

3 sheets-sheet 2 A Filed July 29, 1940 Fmi! B C n wm MR w \\|Ir s nu :inventor:

HAYDEN EJLKLINF. Louis gERYER attomgg Feb. 5, 1946. H. B. KLINE Erm. 2,394,519

"IANUFAGTURE oF 'rnnmn'on THE LIKE Filed July- 29, 1940 3 'sheets-sheet 5 @BERT DMN: LAU RIN fnd-7%@ Patented Feb. 5, 1946 UNITED STATES PATENT OFFICE MANUFACTUBE F THREAD 0R THE LIKE Application July 29, 1940, Serial No. 348,232

'I Claims.

This invention relates to the manufacture, by the extrusion of a coagulable mass into a liquid which serves to solidify it, of strands, strips,

sheets, tubes, threads, laments, etc., hereinafterreferred to as thread." More particularly, the invention relates to the treatment of such liquid for the purpose of rendering substantially innocuous otherwise objectionable substances formed by the coagulable mass and coagulating liquid during coagulation operations. For convenience, the invention will be described in connection with the manufacture of multiple lament viscose artificial silk thread, although it may be employed to advantage, at least in certain of its aspectsI in connection with the manufacture of other products formed by the extrusion of a coagulable mass into a coagulating liquid.

Multiple filament artificial silk viscose thread is formed by extruding an aqueous solution of sodium cellulose xanthate (viscose") through a multiple-orifice spinneret of noble metal or noble metal alloy into an acidic coagulating liquid. The coagulating liquid ordinarily includes sulfuric acid, sodium sulfate, a small amount of zinc sulfate, and, if desired, other beneficial substances. After its extrusion from the spinneret, the sodium cellulose xanthate reacts to form, on one hand, the regenerated cellulose of which the thread is primarily composed and, on the other, such by-products as sodium sulfate, carbon disulfide, hydrogen sulfide and free sulfur, some of which are undesirable. Sundry impurities; viz., hemi-cellulose, complex sulfur compounds, and insoluble compounds of silicon, lead, zinc and occasionally nickel are also introduced into the thread-forming system from the viscose and other sources.

If such substances are not rendered substantially innocuous by continuous removal of the impurities from the coagulating liquid, their presence will soon cause serious operating difilculties. The concentration of such impurities, and hence the magnitude of the resulting difiiculties, tends to increase rapidly during the coagulation operation as a result of the necessity, at least in commercial practice, of repeatedLv recirculating and reusing the coagulating liquid. Because of the large amount of relatively expensive coagulating liquid employed per unit of thread, it is commercially impracticable to use the coagulating liquid only once and then discard it. The nature of the difficulties brought about by this state of aiairs is well understood in the art but will be described briefly hereinafter.

Insoluble impurities, such as sulfur, cause trouble when the viscose of which the thread is to be formed is extruded through the spinneret. Unless special precautions are taken. the orices in the spinneret soon become clogged or fouled by insoluble substances which deposit in craterlike formations around the oriiices on the face of the spinneret. At the same time. ring-like deposits tend to form within the spinneret orices: such ring-like formations appear to be caused primarily by substances in the viscose, such as cellulose, hemi-celluloses, silicates, etc., which precipitate in the spinneret orifices on being subjected to the action of the acid coagulating liquid. Deposits so formed in and about the spinneret oriilces tend to reduce the denier of the individual filaments and often to block the orifices completely. In' the course of the spinning operation, these factors cause considerable diiiiculty, usually producing broken filaments cr snarls of the type known to the trade as fishhooks.

It is not unusual under ordinary spinning conditions to have to replace 20 per cent or more of the spinnerets for such reasons each twentyfour hours. inasmuch as a plant of moderate size will have about 10,000 spinnerets in operation at one time, this means that a very substantial amount of time and labor is lost in making replacements. The economic loss is great even in discontinuous processes of manufacturing viscose artificial silk thread; i. e., in potand spool-spinning processes in which the thread passes directly from the spinneret to a collecting device of limited capacity. The difiiculties arising out of such conditions and the economic waste accruing therefrom are, however, vastly greater when viscose artificial silk thread is produced by so-called continuous processes.

In the continuous process, the thread proceeding from the spinneret to the collecting device is subjected to processing treatment on a series of thread-advancing devices each of which continuously but temporarily stores the thread in a large number of generally helical turns. When, in such a process, a thread breaks because of a clogged or fouled spinneret or is intentionally broken for necessary cleaning or replacement of the spinneret, all of the thread store devices to which the thread would subsequently pass, which may be as many as ten or more, must again be threaded up; that is to say, the leading end of the thread must be passed in sequence to each'of said devices and caused to wind thereon in the required number of generally helical turns.

'rhresd leaving the consultan; man usually tends to carry with it extraneous substances present in the coagulant. Ii such substances are of suillcient concentration, they may interfere Awith the aftertreatment oi' the thread, as, for ex ample, by causing objectionable side reactions.` Under other` conditions, they deposit on parts of the apparatus with which the thread comes into contact, forming incrustations which damage the thread. In continuous processing apparatus, interference with the after-treatment of the thread and the formation of such deposits'are most likely to occur on the thread-advancing devices, The thread passes to such devices from the coagulating liquid within a very short time after its formation and is stored thereon during aftertreatment for a sumcient period of time to favor.Z 3 the formation of such deposits or incrustations.y

It is apparent, therefore, that the presence in 1 the coagulating bath of impurities and bil-products of the coagulation reaction is responsible for `many operating diihculties.

The usual method of treatingthe coagulatingy liquid' for the purpose of removing detrimentalv substances is to lter it. This, however, requires considerable liquid storage space, highly eillcient `filtration facilities, and the expenditure of a not 4inconsiderable amount of time and labor to maintain the equipment in operating condition. Moreover, even after they coagulating liquid is filtered, clogging or fouling of spinnerets tends 1to occur because of the presence of insoluble sub-v stances formed by the reactions which take place :in the course of the solidication of the thread. Because of the colloidal character of certain of `the substances presentin the coagulating bath, particularly sulfur, it is sometimes dimcult, if not actually impossible, to remove such Substances by ltering operations.

All such diiilculties, arising from the presencer of impurities in the coagulating liquid or viscose, are obviated by the present invention, according to one aspect of which a water-insoluble substance, preferably an oleaginous substance,'is in corporatedin finely dispersed condition in the coagulating liquid. One or more suitable dispersing or emulsifying agents, which likewise may be, but are not necessarily, of the nature of an oleaginous material, are preferably employed to aid informing a stable dispersion of the irstmentioned oleaginous material. Indeed, the dispersionof oleaginous material in the coagulating liquid maybe so complete as to .constitute an emulsoid. The presence in the coagulating liquid of such material or materials operates as hereinafter explained to render innocuous the relatively high content of impurities present in the thread forming system, particularly in the coagulating liquid: among other things, such material or materials tend to inhibit the formation of harmful deposits not only in and upon the spinnerets but also upon other parts of the apparatus.

Under suitable circumstances, sch material or scenic may' be" reused indefinitely 'without reunir; spin.

nerets, guides. thread-advancing devices, etc.

For purposes of illustration, the invention will be described in connection with the manufacture of multiple illament viscose artificial silk thread on apparatus of the type disclosedin application' Serial No. '1.1.14 (Patent 2,225,842) illed February 18, 1935, by W. F. Kneblisch and A. H. Burkholder.

In the accompany drawings, Figure l. represents a sectional elevation from line I-i of Figure 2 of a portion( of such apparatus including the thread-forming portion. together with certain of Figure 2 is a front the after-treatment stages. elevation of said Portion ofthe apparatus from line 2-2 vof Figure 1,vv some'oi' the Parts'intermediate the ends of the apparatus beingomitted for convenience or illustration. `Figure 3 is a diagram of a preparation and circulation system for'handling the coagulating liquid according to the present invention. Figure 4 is an isometric' representation of a settlingtank which may bev employed in connection-with the system shown lin Figure 3. Figure 5 is a representation of a modified portion of said tank. ,Y

In the apparatus illustrated in Figures l threads I are formed'by the extrusion of viscose through spinnerets 2 disposed in coagulating bath 3 contained in trough 4. vThread Vi lfrom eachv spinneret passes in turn to each of a plurality of thread-advancing devices 5, 6, 1, 1,1, etc.,

which, Vin the preferred embodiment oi' thejinvention, take4 the Vform of cantilever threadadvancing reels similar `to that shown vin said Patent 2,225,642. Thereels are preferably.k disposed in stepped Varrangement with the unsupported lends of all reels on the same side of the apparatus extending',- toward the corresponding operating f ace of the machine, so that the threaddischarge end of each'reel maybe in' apposition to the thread-receiving endof the succeeding reel. A

5, are thread guides i0. Such guides, which may take any suitable form, serve in eachl case to guide the thread to `the thread-receivingV end of the reel to which it is desired that the thread shall pass. Between reel 5 above coagulating trough 4 and reel 6` below said trough, thread I travels through a vertical channel Il mountedin juxtaposition to the coagulating trough.

Channel Ii `provides an open, unobstructed vpas'- sageway for the thread in its travel from reel 5 to reel 8.

In the apparatus illustrated in the drawings,"

a plurality of thread-producing units, each of which comprises a spinneret 2, a reel 5, a channel Il, a series of reels 8, 1, 8, 9,'etc., and associatedk appmatus, is disposed along each side of av common longitudinally extending coagulating trough "4. By an arrangement of this type, a large thread-production capacity can be obtained in* a materials will form a sludge, iioating, suspended( 65 :illtering the coagulating liquid may be entirely' eliminated; indeed, the same coagulatingliquid very compact space. As is apparent from Figures 1 and 2; corresponding partsof the thread-producing units on each side of the apparatus are disposed in corresponding positions lengthwise of the apparatus, thereby providing operating and constructional advantages. 1

In the illustrated apparatus, no processing medium of any kind is applied to the thread'on the reel above the coagulatingv trough:l said reel serves simply to store the thread for a period long enough to permit coagulation of the freshly spun thread to proceed substantially to comple- Interposed between successive thread-advanc-- ing reels, and also betweenspinneret 2 and reeltion. However. additional coagulating liquid may be, and preferably is, applied to thread I while it is on reel 8. -Washing liquid may be applied to the thread on reel 1; desulfurizing liquid on reel 8; washing liquid on reel 9, etc. In this manner, all of the desired processing treatments may be performed upon the thread.

It will be noted that in each case the liquid is applied to the thread on the reel from a reagent distributing tube l2 which communicates with a Supply conduit I 3 extending longitudinally of the apparatus above the horizontal series oi.' reels of which such reel forms a part: said conduit may be supplied with processing liquid from any suitable source. Below each of the reels on which processing liquid is applied to the thread is disposed a collecting trough I4 which likewise extends lengthwise of the apparatus. Each of said collecting troughs may communicate 'with the sewer or, if desired, with make-up and recirculating means for the processing liquid.

In the apparatus of Figures 1 and 2, reels 8 to 9, inclusive, of each downwardly-extending series of reels are positively rotated, as by means of inclined drive shaft I5 and gears I8, from a drive shaft I1 extending longitudinally of the apparatus along each side thereof. On both sides of the apparatus, the reels 5 disposed above the coagulating trough are driven by means of gears contained in gear boxes I9 from a common longitudinally-extending drive shaft I8. Drive shafts I1 and I8 are driven from common drive means in housing 2| which drive means also rotates 'drive shafts 22, one of which is disposed along each side of the apparatus for the purpose of driving viscose pumps 23. Viscose pumps 23 are supplied with viscose from a longitudinallyextending conduit 24, each pump serving to convey the viscose to its associated spinneret 2 through tube 25 and mass tube 28.

While the coagulating liquid 3 contained in trough 4 may be supplied and recirculated by various means, that shown in the illustrated embodiment of the invention has been found tobe particularly satisfactory.

As is apparent from Figures 1, 2 and 3, the coagulating liquid is supplied to the coagulating trough 4 from means disposed at one end thereof.

The liquid is pumped to an elevated supply box through drain conduits 34 disposed in such trough at intervals therealong. Such drain conduits communicate with a common discharge conduit 35. Preferably the inlet to each of said drain conduits 34 is disposed, as shown, at a sumcient distance above the bottom of the trough to maintain the liquid level in the trough at the desired height. Suitable trap or strainer means 35 are provided at the inlet to prevent entrance into the discharge ducts of material which might clog them.

As shown diagrammatically in Figure 3, supply box 21 is provided with an overow conduit 31 which serves as an emergency drain should the liquid be supplied to said box at a rate greater than that at `which it is removed therefrom. coagulating liquid leaving trough 4 through conduits 34 and 35 passes to vwhat-might be termed a make-up tank 38 from which it ilows through conduit 39 to a storage tank 4I, a valve 42 being provided in said conduit 39 to regulate the flow. From storage' tank 4I the liquid is pumped by pump 43 to supply box 21 through conduit 44, thus'completlng the recirculating cycle. If deaired, a valve 45 may be provided between the tank 4| and pump 43 to regulate the ilow of fluid from the tank to the supply box.

Because of the addition to the system ofextraneous liquids, such as water present in the viscose which is being coagulated, a. conduit '48 is provided which, through regulating valve 41, may be used to bleed o5 any desired amount of liquid from discharge conduit 35.

Sodium sulfate. one of the by-products of the coagulation reaction, tends to increase in amount because of the fact that it is being continuously formed as a result of the reaction.V The addition of water present in the viscose being coagulated dilutes the solution; consequently, if no other precautions were to be taken, the sodium sulfate would eventually reach and maintain an equilibrium concentration of about 15%. It is usually desired to have a higher concentration 'of sodium sulfate; e. g., about 20%, by weight, in the coagulating liquid. Accordingly, as in the case of most commercially used coagulating baths, it is necessary to increase the concentration of sodium sulfate by suitable means.

In the illustrated embodiment of the invention, this is done without the addition of sodium sulfate from any external source by continuously bleeding off through conduit 48 a portion of the coagulating liquid which passes through conduit 44 on its way to coagulating trough 4. The portion so bled oil is conducted to an evaporator 49, indicated diagrammatically in Figure 3. The evaporator, by removing some of the water, increases the concentration of sodium sulfate and other involatile substances in the coagulating liquid. The concentra-ted liquid is then passed through conduit 5I to make-up tank 38. Valves 52 are provided' to regulate the ow of liquid through evaporator 49 which is operated under such conditions that the concentration of sodium sulfate in the liquid passing through conduit 5I is maintained at the desired value.

From time to time, or, if preferred, continuously, reagents may be supplied to replace those consumed in the coagulation reaction or removed with the portion of liquid bled off through conduit 48. In the circulation system of Figure 3, such additions are made in make-up tank 38. Concentrated sulfuric acid, for example, may be supplied from a container 53 through a line 54 embodying a regulating valve 55. Water may, if needed, be added from a tank 56 through a suitable conduit 51. Zinc sulfate may be added in solid form or in aqueous solution. In the system.

- As shown in Figure 4. storage tank 4i is divided by a partition 64 into a large compartment 62 anda small compartment 63. The coagulating liquid is admitted to the large compartment of the tank by means of conduit 36 and leaves the tank through a conduit 44 communicating with the small compartment. Partition 64 is provided Vwith a weir notch 65 through which the liquid from the large compartment overflows into the small compartment. In the embodiment of the invention shown in Figure 4, a removable baille plate 66, preferably of semi-circular cross section. is disposed above said welr notch 65 to prevent fioatlngsludge from overflowing from the liquid in. large compartment 62 into small compartnient 63.

- The system shown diagrammatically in Figure 3 contemplates the thorough mixing together of the coagulating liquid and the oleaginous material to which reference has already been made,

to which end a previously prepared aq'ueous dispersion of the latter is introduced into the former in the small compartment 63 of storage tank 4i by means of pipe 61. The high degree of turbulence in small compartment 63 caused by the suitable sources, such as tanks 69, and I I.y

Thus, in one instance,` a highly refined petroleum oil (white oil) may be supplied from tank 69 through conduit 13, while from tank 10 a less highly refined petroleum oil (mineral oll) may be supplied through conduit 14. Of course, an appropriate quantity of a single oil of suitable characteristics may be added instead. Preferably, an emulsifying agent which will cause such oleaginous liquid or liquids to form'a stable aqueous emulsion is added from container 1i through conduit 15. Water is added through line 12 i such quantities as may be needed.

. The substance sold by the Standard Oil Co. of Ohio under the trade-name Sohio-X Soluble Oil, which substance is understood to be an alkali metal salt of a sulfonated hydrocarbon oil,

has been found to be a satisfactory emulsifyingV agent. This substance, which is soluble in water, is substantially insoluble in the coagulating liquid, but nevertheless gives a finely dispersed emulsion of mineral oil. Preferably, the emulsion is made up in the following manner: approximately 600 poundsof white oil (80 seconds Saybolt viscosity at 100 F.), 600 pounds of No. 17 mineral oil (80 seconds Saybolt viscosity at 100 FJ, and approximately 30 pounds of an approximately 20% aqueous'solution of vohio-X Soluble Oil are mixed with enough vpinatr to bring the total weight of the mixture u to 2000 pounds.

Y The prepared emulsion to be added to the coagulating liquid thus contains, byiweight, about 60% of petroleum oil emulsiiied by approximately .3% of an emulsifying agent in about 39.7% water. In other words, in the present example, the petroleum oil is emulsied by an emulsifying agent added in the proportion of about .5%, based on the weight-of the petroleum oil. Successful results may, however, be obtained with as little as .2% or as much as 2% or more of this or a similar .acting1 emulsifying agent, based onthe weight of the oi The oils, emulsifying agent and water are thoroughly mixed in mixing tank 68. passed 5 through pipe 16'to an emulsifying mill 11, and passed thence to a storage tank 18 from which the mixture proceeds through pipe 61 to the small compartment 63 of storage tank 4l, valve 19 being provided to regulate the rate of flow. i 1 y The concentration of oleaginous material malntained in the ycoagulating liquid may vary considerably and is to a large extent determined by the results desired. v Thus if it is desired that the oleaginous material not'only inhibit depositions,

l5 Von the spinneret but also operate to remove insoluble impurities from the coagulating bath by sludge formation and to lubricate succeeding parts of the apparatus, such as guides, reels, etc., with which the threaxilfcomesy into contact, a higher 20 percentage ofV oleaginous material is desirable in the coagulating liquid'than'if the oleaginous mae terial is required only Vto inhibit the formation of depositions on the spinnerets. A dispersion of from .3% to 3.0% of oleaginous material in the coagulating liquid will make possible the'performance of all of the above-indicated functions. In practice, using the indicated oils, percentages between .5% and 1.5% have been found to provide the best results.

,The coagulating liquid containing the finely dispersed oleaginous material is passed fromk small compartment 63 of 'storage tank 4I to coagulating trough 4: when, therefore, viscoseis.

extruded through the spinnerets, the thread is formed in and coagulated by a coagulating liquid containing, besides the usual ingredients, a'flnely dispersed oleaginous material. As indicated above, the liquid leaving the coagulating trough returns to storage tank 4I by way of conduit 35,

40 make-up tank 38, and conduit 39.* Preferably,

storage tank 4i 1s constructed so ythat large compartment 62 has a very large capacity, even several thousand gallons, so that the coagulating liquid is'stored therein for a considerable period of time before it eventually overflows partition 64.

During this period of time the oil-laden impurities tend to form a sludge Jwhich usually floats onvthe top of the liquid in the large compartment 62 of ,storage tank 4l but which may, under certain conditions, settle to the bottom thereof, the intermediate portions of the liquid being ordinarily free from detrimental substances. Because of the arrangement of bailieplate 66,

in compartment 62 cannot ow over weir notchv 65; consequently, only-substantially uncontaminated liquidfrom beneath the surface, underV the lower edge of baille plate 66. flows on through the system. Batlle plate 66 thus serves to pre-l vent the sludge from `being recirculated with the rest of the coagulating liquid. Such sludgeis removed continuously or from time to time, as desired; for example, the floating sludge which normally forms in large compartment; 62 may be 65 rienliioved by scooping it from the surface of the l q d. 'f .1'

Under the conditions above described, the emulsion of oleaginous substance in the coagulating liquid is suiliciently stable to permit the emulsi-v ed liquid to pass from storage tank 4| to and through coagulating trough 4 andV back to the large compartment 62 of storage tank 4| before the occurrence oflany appreciable separation of the emulsion or the formation ofyan appreciable amount of sludge. Thus serious difiiculties which sludge floating on the surface of coagulating liquid might otherwise be introduced by sludgingof the impurities while the coagulating liquid is still in coagulating trough 4 are avoided. Indeed, the emulsion is so stable that it does not break even when aportion of the coagulating liquid passing to coagulating trough I is,as shown in Figure 3, diverted and passed through a coagulating liquid evaporator where it is subjected to an elevated temperature and a reduced pressure for a considerable time.

As an example, under the conditions above outlined, the coagulating liquid containing the emulsion -formed as described may be subjected in evaporator 49 to evaporative conditions involving a vacuum of from 26 to 27 inches of mercury and a temperature of from 45 to 50 C. for an hour or more without breaking of the emulsion, during which period water in the amount of to 20% of the original weight of liquid is removed.

At suitable intervals, storage tank 4I may be disconnected from the circulation system for cleaning, this being a simple matter if the circulating system includes several such storage tanks 4|. To that end, valve IS through which liquid passes from small compartment 63 of `atorage tank 4I is closed. as is valve 19 which supplies the emulsifled oleaginous material to said compartment. Coagulating liquid flowing into storage tank 4I through conduit 39 is permitted to iiow into small compartment 6.3 through weir notch 65, When the level of. the liquid in compartment 63 reaches the lower edge of outlet duct 8l, the lower edge of which outlet duct is below the top of partition 84, baille plate 66 is removed and dam plate 82 substituted therefor.

As shown in Figure 5, dam plate 82 blocks weir notch 65, thus providing a substantially even surface along the top of partition 6l. The liquid flowing from large compartment 62 into small compartment 63 then flows in a thin stream over the entire length of partition S4 carrying the oating sludge with it without creating undue turbulence, thus obviating dissemination of the sludge in the liquid in small compartment 63'. All of the sludge passing into the small compartment 63 oats on the surface of the liquid therein and passes out through outlet duct 8|; however, its removal may, if desired, be facilitated by scooping it out. When the liquid in storage tank 4i is substantially free of sludge, the valie may be reopened, baille plate 66 replaced, and valve 'I9 in pipe 61 reopened, after which the storage tank may be rejoined with the system.

Under the conditions above outlined, most of the agglomerated insoluble impurities such as sulfur which are present in the liquid contained in storage tank 4I nd their way into the sludge which forms on the surface of the liquid in large compartment 62 of storage tank 4|. A small amount of the petroleum oil separates from the emulsion in the form of a layer which floats on the surface of the coagulating liquid immediately berief` th the sludge layer. When the sludge is scooped from the surface of the liquid in the tank or the tank is cleaned as above described, some of such separated oil may be removed.

It has been found that, under suitable circumstances, the colloidal impurities present in the coagulating bath. particularly colloidal sulfur, can be caused to aid the emulsifying agent in forming ar. emulsion so stable that substantially no oil separates even though the coagulating liquid requires several hours for circulation and is subjected to the aforementioned drastic conditions in the evaporator. This can be accomplished by increasing the proportion of the oleag inous emulsifying agent to the other oleaginous substances employed. Thus, using .the above- 5 indicated substances, this result can be obobtained by employing about 2% or more of the emulsifying agent based on the weight oi' the petroleum oil, which petroleum oil, as stated. is preferably in the neighborhood of 1% by weight of the coagulating liquid.

Under such a mode of operation, not only is the petroleum oil inhibited from separating from the emulsion, but the insoluble impurities such as sulfur, which apparently aid in maintaining the stability of the emulsion, precipitate from the yemulsion only in storage tank 4I. Since nopetroleum oil is permitted to separate from the emulsion in the coagulating trough, very little, if any, is lost from the system other than that carried out of the coagulating bath by the thread; indeed, over a long period of time it is only necessary to add an emulsifying agent, and that rarely, to replace the amount carried out of the circulation system. In such case, storage tank Il may be drained and cleaned from time to time in the manner indicated.

In the circumstances above described, the coagulating liquid therefore has iinely dispersed therein, as by emulsication, a finely divided oleaginous material normally insoluble in the coagulating liquid. The thread is formed in the presence of such dispersed oleaginous material. The oleaginous material under conditionssuch as those described above inhibits, if not entirely prevents, the formation of harmful deposits of sulfur and/or other substances in and upon the spinnerets. In particular, it inhibits, if it does not entirely prevent, the formation of harmful crater-like deposits around the spinneret orifices. which crater-like deposits arise primarily from insoluble impurities in the coagulating liquid, and the formation of harmful ring-like deposts in the spinneret orifices, apparently arising primarily from impurities in the viscose. Whatever 45 deposits may form are soft, harmless, and easily removed.

Such oleaginous material also promotes the agglomeration of insoluble contaminants. such as sulfur, which are present in the coagulating liquid and facilitates their separation from the coagulating liquid either continuously or from time to time. The oleaginous material also lubricates the spinnerets and thread. In this connection, the oleaginous material carried by the thread forms films on the parts of the apparatus with which the thread comes into contact after leaving the spinneret, such as guides or reels,

and inhibits the formation on such parts of the.

apparatus of precipitates or deposits of contaminants which would damage the thread by snagging or abrading it.

Under suitable circumstances, it is possible to obtain a desulfurizing action on the thread in the coagulating bath, so that considerable sulfur may be removed from the thread before it even leaves the coagulating bath.

Modications may be made in the foregoing example of the preferred method of practicing the invention. The proportions of dispersing or emulsifying agent to the oleaginous material may be varied, depending upon the nature of the agent; indeed, two or more substances may act together to form the dispersing or emulsifying agent. Moreover, as indicated, the amount of 7 oleaginous material dispersed in the coagulating liquid ie-to fluege extent dependent upon whether functions in addition tolthose of inhibltv .ing spinner-et depositions areA desired Aoi'-the oleasinous material. The example which follows is illustrative of another method of practicing the invention.

- A soluble oil is made up consisting. vby weight,

oi' 50% lrefined petroleum oil of 30 seconds Say* bolt viscosity at 100 F., 12% sorbitol monolaurate. and 38% of a 50% aqueous solution of modifled (solubilized)- sorbitol monolaurate. The

-modiiied sorbitol monolaurate has been treated with ethylene oxideto render it soluble and ls supplied-by the Atlas Powder Company. A710% aqueous dispersion is formed of this liquid, either `by means of an emulsifying mill, as previously described, or merely by addition of the liquid to i the desired quantity of warm water. The emulsion thus formed is added to the coagulating liquid. :The unmodified sorbitol vmonolaurate` and ciently to disperse the petroleum oil.

,'.amplea spinneret's of 00% platinum 'and 10% rhodium are less likely tobecolne contaminated/i than splnnerets Ii'ormed Aof an "alloy of 80% sold and 20% palladium. :Ilreither4 case, however,

the number of spinnerets whichmust be replaced or cleaned las a result of contamination is far y less when the present invention is employed than the number which must be cleaned orY replaced in the absence of use of the present invention.

Variousaother modincations may be made inl the methods and. apparatus hereinabove. de-

scribed without departing from the spirit of the the modified sorbitol monolaurate cooperate ef- Ayery stable emlllsion of the oleaginous ma'- terial vinthe ooagulating liquid ls obtained which emlllsion is, however, very effective even if only minute quantities ofthe oleaginous material are dispersed in the coagulating liquid. Fouling of spinnerets by the formation of deposits about or in the orinces is almost non-existent even though,

by weight, less than 500 parts of the above-described soluble oil are dispersed in a million parts Y of coagulating liquid. Extremely good results in invention. The described oleaginous materials and emulsifying agents arenotthe only materials whichmaybe employed for the-purposes y of the present invention. yThere mayiber employed one or more of several other organic yol' `inorganic materials, preferably but not necessarily oleaginous, whichare capable of being dispersed inthe coagulatlng liquid and which, because of their nature, have an affinity for such insoluble impurities, even if of colloidal form, as are present in the coagulating bath.

Numerous types of substances, either soluble or insoluble in the coagulating liquid, maybe employed as kdispersing or emulsifying agents.

As examples of suchagents maybe mentioned the sulfated and sulfonated higher alcohols and eral, vegetable or animal types, may also be emesters, including the sodium or potassium salts, of such sulfated and sulfonated hydrocarbons. Sulfated and sulfonated oils, either of the minployed as dispersing or emulsifying agents. Ex-

amples are'sulfonated petroleum, castor or coconut oils and the so-called` Twitchell oils, each of which latteris made up of a baseconstituting a sodium salt of a sulfonated hydrocarbon dis- Y solved in mineral oil. SomeTwitchell oils are substantially insoluble in they ooaguluti'ng liquid while others are soluble: both types make satisfactory emulslfying agents.

insoluble impurities from the coagulatillg liquid by filtering or similar methods, since the amount of oleaginous material may be insufficient to permit the removal o'f such substances as a sludge. However, even such small quantities of oleaginous material cause someV agglomerationV of particles of impurities such as sulfur, thus facilitating the removal of such substances by filtering tions.

Similar-results may be obtained with small quantities of the petroleum oils and the Schio-X Soluble Oilused as the emulsifyin-g agent in the rst example. Likewise, the various functions other than thatof inhibiting spinneret contamination described above in connection with the ilrst example may be obtained bythe use of a mixture of the type described in the second ex- Vvample provided that larger amounts of the mix- Operafor example, as the compound Gil ture are employed. In such case, the amount of oil in the coagulating liquid is preferably within Y the range mentioned in connection with the rst example.

In each of the two examples described above, moreover, it appears that more elcient action in inhibiting deposits in or about the spinneret oriiices is obtained by the use oi oils of lower viscositynumbers than by the use of oleaginousV vmaterials of higher viscosity numbers. Furthermore, it appears that the nature of the alloy of which the spinnerets are vformed plays a part in the efiiciency of the action of the dispersed oleaginous material in inhibiting depositions upon the spinnerets. Thus in `each of the illustrated ex- Certain esters of sulfodicarboxylicacids, such as the sodium salt of dilauryl sulfosuccinate sold as Deceresol by the American Cyanamid and Chemical Corporation, are kalso useful for dis-ll persing agents in the practice of the invention. Sulfuric acid derivatives of certain amides, such, having the formula .A om cmnmcmcnomiicoNCHlCHisOlNn 1 lsold by the Colgate-Palmolive-Peet Corporation under the trade-mark Arctic Syntex, are likewise eilicientfdispers'ingagents for the purposes of the present invention.

While the inventionhas been described in detail in connection with the manufacture of multiple filament viscose artificial silk thread by a continuous process, it is apparent that it is equally applicable to discontinuous processes, such as spool-.and pot-spinning processes. Moreover,

the invention is not restricted to the manufacture of viscose artificial silk thread. If desired, it may, at leastfin certain of its aspects, be applied to .the manufacture of other products; e. g3,

strips,` ribbons', tubes,A sheets, etc., by processes which involve generally the extrusion of coagulable masses into liquid coagulants.

The term spinneret," wherever employed in the claims, is intended to include other types of extrusion heads than the usual thread-forming spinnerets. The term "impurities is intended to include such insoluble substances as sulfur,

colloidal orotherwise, produced as a result of i the coagulation reaction oi' the viscose thread.

It is also intended to include other insoluble subq stances in the coagulating liquid, together with substances such as silicates, hemi-celluloses or other substances which tend to form deposits on the spinnerets or in the orices thereof.

It is intended that the patent shall cover, by suitable expression in the appended claims, Whatever features of patentable novelty reside in the invention.

What is claimed is:

1. In the formation of cellulosic materials by the viscose process, the steps which comprise extruding viscose into an acidic coagulating liquid containing an emulsiiied petroleum oil which is substantially insoluble in said coagulating liquid', permitting said emulsied petroleum oil to form a sludge with impurities in the coagulating liquid and separating said sludge from the coagulating liquid.

2. In the formation of cellulosic materials by the viscose process, the steps which comprise extruding viscose into an acidic coagulating liquid containing an emulsifying agent and an emulsified petroleum oil which is substantially insoluble in said coagulating liquid, permitting said emulsied petroleum oil to form a sludge with impurities in the coagulating liquid and separating said sludge from the coagulating liquid.

3. InV the formation of cellulosic materials by the viscose process, the steps which comprise extruding viscose into lan acidic coagulating liquid containing a sulfonated hydrocarbon and an emulsied petroleum oil which is substantially insoluble in said coagulating liquid, permitting -said emulsified petroleum oil to form a sludge with impurities in the coagulating liquid and separating said sludge from the coagulating liquid.

4. The method of forming viscose thread which comprises extruding viscose into an acidic coagulating liquid containing 'an emulsied petroleum oil which is substantially insoluble in said coagulating liquid.

5. The method of forming viscose thread which comprises extruding viscose into an acidic coagulating liquid containing an emulsifying agent and an emulsified petroleum oil which is substantially insoluble in said coagulating liquid.

6. The method of forming viscose thread which comprises extruding viscose into an acidic coagulating liquid containing an emulsied petroleum oil which is substantially insoluble in said coagulating liquid and an emulsifying agent comprising a sulfonated hydrocarbon.

'7. The method of forming thread by a wetspinning process which comprises extruding a coagulable thread-forming mass into an acidic coagulating liquid containing an emulsied oleaginous substance which is substantially insoluble in said coagulating liquid and an emulsifying agent comprising a sulfonated hydrocarbon, permitting said oleaginous substance to form a sludge with impurities in the coagulating liquid and separating said sludge` from the coagulating liquid. 

